peb2035 ETC-unknow, peb2035 Datasheet - Page 44

• Manufacturer Part Number: peb2035
• Description: Communications Advanced Cmos Frame Aligner
• Manufacturer: ETC-unknow

12-Frame Multiframe
Normally, this kind of multiframe structure only makes sense when using the CAS bit robbing mode.
In addition, CCS and CAS-CC are also allowed. The multiframe alignment signal is located at the
FS-bit position of every other frame (refer to table 7).
There are two possibilities of remote alarm indication:
Synchronization Procedure
In the synchronous state terminal framing (FT bits) and multiframing (FS bits) are observed,
independently. Further reaction on framing errors depends on the selected sync/resync procedure
(via bit EMOD.SSP):
Semiconductor Group
bit 2 = 0 in each channel of a frame, selected with bit CCR.SRAF= 0
the last bit of the multiframe alignment signal (bit 1 of frame 12) changes from ‘0’ to ‘1’, selected
with bit CCR.SRAF = 1.
EMOD.SSP = ‘0’: terminal frame and multiframe synchronization are combined.
Two errors within four/five framing bits (via bit RC1.SLC) of one of the above will lead to the
asynchronous state for terminal framing and multiframing. Additionally to the bit RSR.LOS, loss
of multiframe alignment is reported via bit FSR.MLOS.
The resynchronization procedure starts with synchronizing upon the terminal framing. If the
pulseframing has been regained, the search for multiframe alignment is initiated. Multiframe
synchronization has been regained after two consecutive correct multiframe patterns have been
received.
EMOD.SSP = ‘1’: terminal frame and multiframe synchronization are separated
Two errors within four/five terminal framing bits will lead to the same reaction as described above
for the ‘combined’ mode.
Two errors within four/five multiframing bits will lead to the asynchronous state only for the
multiframing. Loss of multiframe alignment is reported via bit FSR.MLOS. The state of terminal
framing is not influenced.
Now, the resynchronization procedure includes only the search for multiframe alignment.
Multiframe synchronization has been regained after two consecutive correct multiframe patterns
have been received.
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PEB 2035